Their crossing of the Mississippi in the 1790s helped persuade Napoleon to sell the Louisiana Territory to the United States for only 15 million dollars. At one stroke the territory owned by the United States almost doubled.(17世纪90年代,他们横渡密西西比河,说服拿破仑仅以1500万美元的价格将路易斯安那州的领土出售给美国。美国拥有的领土一下子几乎翻了一番。)